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09-16-2008, 06:09 AM   #1
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Cleaning Fungus from a lens

I recently purchased a lens on eBay with some fungus on the inner back lens. I asked my backyard neighbor who is a professional camera repairman if he could clean off the fungus. He indicated that he was reluctant to clean the lens, but would do so with no guarantee. He said the inner coating on the lens is much different than on the outer part of the lens and sometimes he doesn't have good luck and as a result damages the coating. Has anyone out there heard of anything similar or had fungus cleaned off of a lens? Thanks.

09-16-2008, 08:35 AM   #2
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I was going to try the same thing. Might be able to remove the fungus through a chemical bath instead of physical removal. I am going to pick up a lens some time this week to try this out for myself.
09-16-2008, 09:03 AM   #3
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Can you tell me what you see when you look in the lens? I have a beautiful pentax-m 15mm plagued by an ugly mist.

The image of the lens shows what i see when i put my eye to the lens, not what a photograph taken with the lens looks like

The image of my brother shows that there is huge edge misting (even on 1.5x crop!!!), and that photo is taken with aperture closed, With aperture open, the entire image glows, especially where highlights are.

The lens is almost useable stopped down on the k20d, but is pretty much useless on a film camera.
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09-16-2008, 09:37 AM   #4
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I read somewhere that you can wrap the lens in aluminum foil and leave it in the sun for a while to kill the fungus. I never tried it and doubt it would clean it but it might help a little.

Lots of info here.

09-16-2008, 10:05 AM   #5
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QuoteOriginally posted by Slick Quote
I read somewhere that you can wrap the lens in aluminum foil and leave it in the sun for a while to kill the fungus. I never tried it and doubt it would clean it but it might help a little.

Lots of info here.
That's for the yellowed thorium coated Takumars, the UV bath won't do much to kill fungus per https://www.pentaxforums.com/forums/113775-post12.html
QuoteOriginally posted by Peter Zack Quote
Yellowing that you are referring to is for the older Tak 50 f1.4's and a few other similar lenses. They contained thorium as a multi coating that yellowed over time. The tin foil and sunlight trick will work over about 3 weeks of strong exposure to the sun. It wouldn't fix this issue though. Fungus will etch the glass and yellow it with an acid by product of the growth. Once it's affected this way it's done for. 2 different issues with 2 different lenses.
09-16-2008, 11:21 AM   #6
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I would take the lens apart and try to clean it. If it doesn't work you really are not out anything because the lens was already toast anyway (or soon to be). I cleaned some fungus out of my Super Takumar 85mm, and it worked great. I used a 50/50 solution of ammonia and hydrogen peroxide and it dissolved the fungus. Then wiped it clean with some Pec pads and Eclipse fluid. The ammonia/hydrogen peroxide is a nasty concoction though, so if you try this be careful. This will dissolve the fungus, but obviously it will not fix the glass if it is etched already. I say give it a shot.


Edit: I only applied the solution directly to the effected areas, very lightly with a Q-tip swap. Then cleaned off immediately.
09-16-2008, 11:30 AM   #7
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oil

Hello
That looks like someone tried to oil the lens or it got really hot and the factory applied lubricant liquefied then hardened on the lens inside. You should send it to me.
Barry


QuoteOriginally posted by IsaacEastgate Quote
Can you tell me what you see when you look in the lens? I have a beautiful pentax-m 15mm plagued by an ugly mist.

The image of the lens shows what i see when i put my eye to the lens, not what a photograph taken with the lens looks like

The image of my brother shows that there is huge edge misting (even on 1.5x crop!!!), and that photo is taken with aperture closed, With aperture open, the entire image glows, especially where highlights are.

The lens is almost useable stopped down on the k20d, but is pretty much useless on a film camera.
09-16-2008, 11:52 AM   #8
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QuoteOriginally posted by barryr Quote
Hello
That looks like someone tried to oil the lens or it got really hot and the factory applied lubricant liquefied then hardened on the lens inside. You should send it to me.
Barry
Yeah, I'm not really sure that looks like fungus. Take the troubled element out and take a close look at it.

I had a rear element with fungus once; I took it off the lens and left it submerged in a bath of 50/50 acetone and rubbing alcohol. You'll read contradictory opinions about acetone on lenses, but I had to do something or I wouldn't use that lens again. I would not use acetone unless the element has been removed from the lens as it will attack plastics and paint.

However, if what you have is just some stray oil, and this could very well be the case, then a tissue and some rubbing alcohol or hydrogen peroxide is all you'll need.

09-16-2008, 12:06 PM   #9
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how does fungus get into the lens anyway?
09-16-2008, 01:01 PM   #10
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QuoteOriginally posted by Slick Quote
I read somewhere that you can wrap the lens in aluminum foil and leave it in the sun for a while to kill the fungus. I never tried it and doubt it would clean it but it might help a little.

Lots of info here.
You can kill fungus with the UV light. But you won't get rid of the remains, so you need addistional, mechnical cleaning, too.

Ben
09-16-2008, 01:03 PM   #11
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QuoteOriginally posted by marlon Quote
how does fungus get into the lens anyway?
Fungus spores are everywhere in the air. If the climate is right (dark and humid), it will grow...
Ben
09-16-2008, 01:04 PM   #12
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QuoteOriginally posted by Miserere Quote
Yeah, I'm not really sure that looks like fungus. Take the troubled element out and take a close look at it.

I had a rear element with fungus once; I took it off the lens and left it submerged in a bath of 50/50 acetone and rubbing alcohol. You'll read contradictory opinions about acetone on lenses, but I had to do something or I wouldn't use that lens again. I would not use acetone unless the element has been removed from the lens as it will attack plastics and paint.
I would not use acetone. It sure works against fungus, but it can also dissolve the glue (lens cement) between the lens elements. That would be the death of the lens, unless you are able to recement it, which is not an easy task.

Ben
09-16-2008, 01:10 PM   #13
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QuoteOriginally posted by barryr Quote
Hello
That looks like someone tried to oil the lens or it got really hot and the factory applied lubricant liquefied then hardened on the lens inside. You should send it to me.
Barry
Thanks for the help everyone. I really want to get this lens clean so i might try some of the chemicals you have recommended.

I think i had some acetone in my room, plus it smells great, so thats a good start.

You could be right about the oil you know... My dad used it for a while and his friends used it as a travel lens and told me they had given it a proper clean at some point. I was really unsure about that, they dont really know much i dont think so they might have tipped a little oil in. By the patterns and even spread though, it has to be fungus?

Can i take it that from people's experiences this is the kind of thing fungus looks like on a lens?
09-16-2008, 01:15 PM - 1 Like   #14
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I have cleaned several lenses from fungus. In my experience, it is not too difficult, unless the whole lens surface is overgrown, in which case, the fungus may already have left dissolving marks in the glas, which would need to be repolished.

But I never had that.

In some lenses I was able to clean the fungus completely with Eclipse. It worked always better than Isopropanol from the pharmacy, though I am not sure why. I use the PEC pads, apply Eclipse generously and carefully rub the lens surface. You will often read, that the lens gets scratched, when applying some pressure, but you won't get fungus off, withour using some mild force - I never had noticeable scratches. The PEC pads are very soft and lint free.

On one or two lenses, the fungus laughed about the Eclipse and refused stubbornly to be wiped off. In these rare cases I used simply household windows cleaner (buy a clear, traditional variety from an organic shop, no foam or the like) with great success. This way I could even clean the filter wheel inside my Pentax shift lens.

I was contemplating to keep the contaminated lenses in a formaldehyd atmosphere for one or two weeks to completely sterilize them, but in the end, I decided, this was just too much of a mess and too unhealthy, to do.

If you do the cleaning job, just be careful, not to loose any of the small screws and reassemble everything correctly. Some small parts, that fell out of the shift lens, caused severe head scratching, before I could finally place them correctly...

Ben
09-16-2008, 01:48 PM   #15
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Thanks thanks ben. I'll have to look inside the lens and see whats up, i believe it has some cemented elements, and maybe even the first lens to use aspherical elements if i remember my stuff.

Speaking of cemented elements, could it be possible that the optical glue has weakened between the elements and that they are a bit detatched, leaving squiggles where the glue has come out?
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